In recent years, the development of color displays using organic EL devices is actively progressing, and various light-emitting materials and charge transport materials useful for organic EL devices are being studied. It is known that the use of a compound having an excellent hole injection property as the above-described materials in organic EL devices can reduce their driving voltage.
As an example of the compound having a hole injection property, a polymer compound obtained by polymerization of 2,7-bis(4-methyl-4′-bromo-diphenylamino)-9,9-dioctylfluorene has been reported (Patent Literature 1).